"Both H.K. Lin, PhD, and Mahmoud Suhail, MD - who have extensive experience working with frankincense and cancer - recommend using "enriched" Boswellia sacra for cancer. Enriched frankincense is simply frankincense bottles that have been left open to allow the light chemical compounds to evaporate out, leaving the heavier chemical compounds. The bottle is allowed to evaporate until only 20% of the oil remains. According to Dr. Lin, this makes Boswellia sacra 10 times more potent. Because cancer is a devastating disease, aggressive action is often necessary to correct it. Large oral doses are frequently suggested and may be difficult to take immediately; therefore, it is prudent to work up to the recommended dosage to allow the body to adjust. You may start with at 1 quarter of the dosage, then work to half, and then to the full dose over a period of several days to a couple weeks. The same applies for orange oil when indicated. The average essential oil contains from 20-40 drop of essential oil per 1 mL.. This figure can be used as a guide for dosing, but oils vary significantly based on their specific gravity, so it is not perfect. In general, 30 drops per milliliter is a good average.
DISCLAIMER: Cancer is one of the most common life-threatening illnesses that affect up to half of us during our lifetime. You should never attempt to treat it alone. Ideally you will work closely with your physician and determine the best course of action that will lead you to healing. This partnership provides the greatest possibility of successful treatment and survival."

This excerpt is from the book by Dr. Scottt A. Johnson entitled EVIDENCE-BASED ESSENTIAL OIL THERAPY and is my go-to for utilizing essential oils for treatment internally as well as externally. It is informative and extremely well written and indexed and includes extremely important safety information on dilutions and safe oils for pregnancy, birth, children, teens and adults. I highly recommend this book if you are a serious user of essential oils. The different cancers are broken down, so you know how to utilize the enriched frankincense. Also, he includes some homeopathy recommendations. Very excellent investment.